重载列表理解行为?

>>> class MyList(list):
...     def __iter__(self):
...         return (x for x in list.__iter__(self) if x is not None)
... 
>>> 
>>> ml = MyList(["cat", "dog", None, "fox"])
>>> for item in ml:
...     print item
... 
cat
dog
fox

>>> [x for x in ml]
['cat', 'dog', 'fox']
>>> list(ml)
['cat', 'dog', 'fox']

您可以为此提供一个生成器/迭代器。

def installed(cage):
    for card in cage:
        if card:
            yield card

cards = ["Adaptec RAID", "Intel RAID", None, "Illudium Q-36 Explosive Space Modulator"]

# print list of cards
for card in installed(cards):
    print card

如果您使用的是2.6或更高版本,您可以这样做来获取名称:

names = [x.name for x in cards if x is not None]

这应该接近你想要的。

也许定义一个函数(假设卡片是一个全局变量???):

def pcards():
    for card in cards:
        if card:
            print card.name

这样用户就可以简单地输入 pcards() 得到一个清单。